Epitaxial growth is a process for growing a thin film having the same crystalline structure as a semiconductor substrate on the semiconductor substrate.
Also, a process in which an insulation layer such as an oxide layer and a nitride layer is formed on a predetermined area of the semiconductor substrate to expose the predetermined area of the semiconductor substrate, and a homogeneous or heterogeneous semiconductor film having the same crystalline structure as the semiconductor substrate is grown on only the exposed semiconductor substrate is called selective epitaxial growth (SEG). If the selective epitaxial growth is used, a semiconductor device having a three-dimensional structure, which is difficult to be manufactured by using the existing flat panel technology, may be easily manufactured. In a process including the SEG, gas supply and gas distribution on the substrate may be very important.
However, in the typical batch-type selective monocrystal growth device, since a reaction gas sprayed from a side nozzle flows onto upper and lower ends of an inner tube, where an exhaust passage is defined to cause a non-uniform reaction gas flow above the substrate, film uniformity after the film is formed may be deteriorated. Particularly, since a gap exists between the inside of the inner tube and an outer diameter of the substrate, most of the gas sprayed onto the substrate flows into the gap of a side surface of the substrate without sufficiently reacting on the substrate. Thus, it may take a relatively long time to form a film, and flatness in film quality may be reduced.